1. The Field of the Invention
The present invention is in the field of orthodontics, more particularly in the field of devices for correction of class II and/or class III malocclusions.
2. the Relevant Technology
Orthodontics is a specialized field of dentistry that involves the application of mechanical forces to urge poorly positioned or crooked teeth into correct alignment and orientation. Orthodontic procedures can be used for cosmetic enhancement of teeth, as well as medically necessary movement of teeth to correct overjets and/or overbites. For example, orthodontic treatment can improve the patient's occlusion, or enhanced spatial matching, of corresponding upper and lower teeth.
The most common form of orthodontic treatment involves the use of orthodontic brackets and wires, which together are commonly referred to as “braces.” Orthodontic brackets are small slotted bodies configured for direct attachment to the patient's teeth or, alternatively, for attachment to bands which are, in turn, cemented or otherwise secured around the teeth. Once the brackets are affixed to the patient's teeth, such as by means of glue or cement, a curved arch wire is inserted into the bracket slots.
The brackets and the arch wire cooperate to guide corrective movement of the teeth into proper alignment. Typical corrective movements provided by orthodontic treatment can include lateral migration, torque, rotation, angulation, leveling, and other movements needed to correct the spacing and alignment of misaligned teeth.
The orthodontic treatment of some patients includes correction of the alignment of the upper dental arch relative to the lower dental arch. Certain patients have a condition referred to as a Class II malocclusion, which is a condition involving the posterior relationship of the mandible to the maxillae and in which the mesiobuccal cusp of the permanent maxillary first molar occludes mesial to the buccal groove of the permanent mandibular first molar (also known as retrognathia, or overjet). Other patients may have an opposite condition referred to as a Class III malocclusion wherein the lower dental arch is located forward of the upper dental arch when the jaws are closed (prognathia, or negative overjet).
Class II and Class III malocclusions may be corrected with the use of a force-applying system such as headgear, elastic, or an intraoral force module. Headgear is generally disfavored because it is bulky and often a source of embarrassment for the patient. Intraoral force modules have gained increasing acceptance as they can remain fixed in place over the course of treatment so as to typically not be removable by the patient, and are less aesthetically objectionable compared to traditional headgear.
Examples of intraoral force modules are disclosed in PCT Publication No. WO 2012/018648 and U.S. Pat. Nos. 5,828,875; 5,738,514; 5,711,667; 5,562,445; 6,358,046; 6,162,051; 5,964,588; and 5,944,518, the disclosures of which are incorporated herein by reference. Although existing intraoral force modules represent an improvement over headgear, they still have deficiencies that provide opportunities for substantial improvement.